The removal of dams has led to renewed riverine fluxes of sediments and increased habitat through river delta growth and the incursion of woody debris. The increased supply of sediment and natural debris to the fluvial system restored channel morphology to its former complexity and resulted in increased river braiding, sediment-bar growth, and pool filling. With renewed connectivity of these rivers’ upstream habitat and seascape, many are experiencing an increased return of several salmon species (Chinook, coho, chum, sockeye, and pink) as well as anadromous trout (e.g. Steelhead and Bull trout).

In one case study, conducted in the early 2010s on the Elwha River in Washington State, scientists have already observed record numbers of returning Chinook salmon, with high returns anticipated to follow for other species (Law & Moore, 2020). About 30,000 Chinook and coho salmon and 270,000 pink salmon are expected to return annually. Salmon returns will eventually sustain local and regional fisheries. The Elwha is one of many coastal catchments that has protected salmon habitat in its headwaters but whose connectivity to the seascape was severed. As illustrated by the Elwha project, dam removal and restoration of the free-flowing status of rivers can effectively connect protected headwaters with the seascapes on which migratory fishes such as salmon depend.